Composite printing plate

ABSTRACT

Composite printing plate for relief and/or photogravure printing, characterised in that it consists of a support layer of aluminum or aluminum alloy of very low tin or zinc content, and of an aluminum-zinc layer clad onto one side of the support layer.

United States Patent 1191 Bretthauer et al.

[ Dec. 30, 1975 COMPOSITE PRINTING PLATE [75] Inventors: Klaus Bretthauer, Volkertshausen;

Erich Simon, Singen, Hohentw, both of Germany [73] Assignee: Swiss Aluminum Ltd., Neuhausen am Rheinfall, Switzerland 22 Filed: Feb. 27, 1974 21 Appl. No.: 446,121

[30] Foreign Application Priority Data Mar. 7, 1973 Germany 7308584[U] [52] U.S. Cl. 101/395; 101/150; 101/459;

29/l97.5; 75/146; 75/147 [51] Int. Cl. B41N 1/06 [58] Field of Search 101/459, 458, 401.1, 395,

lOl/150; 29/1975; 75/146, 147

[56] References Cited UNITED STATES PATENTS 1,083,890 l/19l4 Smith 101/395 HI] 1111 I11 I 2,290,026 7/1942 Bonsack 75/146 3,136,672 6/1964 Prongay 101/395 X 3,475,140 10/1969 Russell 101/458 X 3,717,915 2/1973 Teubler 101/459 X OTHER PUBLICATIONS Book Production Industry; Vol. 41, No. 12; Dec. 1965, pp. 38-41.

Primary ExaminerCliff0rd D. Crowder Attorney, Agent, or Firm-Ernest F. Marmorek 571 ABSTRACT Composite printing plate for relief and/or photogravure printing, characterised in that it consists of a support layer of aluminum or aluminum alloy of very low tin or zinc content, and of an aluminum-zinc layer clad onto one side of the support layer.

2 Claims, 2 Drawing Figures US. Patent Dec. 30, 1975 3,929,073

mnnmu umu COMPOSITE PRINTING PLATE The invention presented here concerns a composite printing plate, which finds use in relief and/or photogravure printing, and which in its construction is based on aluminun.

Printing plates produced from two or more layers of different metals are well known. Such plates however consist of a zinc alloy containing only little aluminun, clad on an aluminum alloy.

By way of contrast to this, the object of the invention is a printing plate exhibiting an AlZn layer, containing 0.2-l percent Zn, preferably 0.5-2 percent Zn, rolled onto one side of a supporting material. This support layer which is also known as the core layer consists of aluminun or a suitable aluminum alloy which may contain tin or zinc only as impurities. In particular an aluminum alloy, containing 0.2-5 percent Mn, preferably 0.5-2 percent Mn is used. This alloy may also contain 0.1-0.5 percent Mg.

The layer of AlZn cladding should be able to be etched away as quickly and as uniformly as possible, the core layer on the other hand shoud exhibit high strength, formability and resistance to the etchant.

For the manufacture of the composite plates the AlZn billets, after annealing at approximately 400C for 1 hour, are hot rolled down to a thickness of, for example, percent of the thickness of the core billet and, in plate form, laid on top of the core billet. The two materials are then annealed in contact with each other for 1-4 hours at a cladding temperature lying between 400 and 450C, preferably at 420C, and finally hot rolled to 7-9 mm. The final thickness of the composite plate is arrived at by cold rolling. This, as a rule, is at about 1 mm thickness.

By etching with pure dilute hydrochloric acid which has no additives in it, the AlZn cladding is completely removed at the desired places in a short time; the substrate which is low in tin and zinc is on the other hand almost unattacked by the etchant. The relief height or depth is given by the different etching behaviour of the materials. No edge protection agent is necessary.

The innovation is illustrated in greater detail by way of an example in a drawing which follows and shows:

FIG. 1 Schematic section through a composite printing plate before the etching process.

FIG. 2 Schematic section through a composite printing plate after the etching process.

The substrate layer 1 of a suitable Al alloy has been clad with an AlZn layer. This layer is masked with an acid resistant partial layer 3. On etching in pure dilute hydrochloric acid the AlZn layer is completely removed on the areas not masked; the support layer is almost unattacked.

EXAMPLE An aluminum alloy billet containing about 1 per cent zinc was annealed at about 400C for about 1 hour and then hot rolled down to a plate whose thickness was about 10 per cent of that of the core billet to be used. This cladding plate and the aluminum alloy core billet, which contained about 1 per cent manganese and about 0.3 per cent magnesium, were annealed in contact with each other for about 4 hours at about 420C and then hot rolled to about 7 millimeters. The final thickness of about 1 millimeter of the composite material was arrived at by cold rolling.

The cladding layer was masked at the places which were not to be attacked by the etchant. The cladding at the places not masked was completely removed with pure dilute hydrochloric acid. The support layer was not or only negligibly attacked by the etchant.

What we claim is:

l. A printing plate formed of a composite material, comprising a support layer consisting of from 0.2 to 5 per cent manganese, from 0.1 to 0.5 per cent magnesium, zinc and tin at most as impurities, and the balance being aluminum and a clad layer consisting of from 0.2 to IO'per cent zinc and the balance being aluminum clad onto one side of said support layer.

2. The printing plate as claimed in claim 1, wherein for said support layer the manganese content is in the range of from 0.5 to 2 per cent and for said clad layer the zinc content is in the range of from 0.5 to 2 per cent. 

1. A PRINTING PLATE FORMED OF A COMPOSITE MATERIAL, COMPRISING A SUPPORT LAYER CONSISTING OF FROM 0.2 TO 5 PER CENT MANGANESE, FROM 0.1 TO 0.5 PER CENT MANGNESIUM, ZINC AND TIN AT MOST AS IMPURITIES, AND THE BALANCE BEING ALUMINUM AND A CLAD LAYER CONSISTING OF FROM 0.2 TO 10 PER CENT ZINC AND THE BALANCE BEING ALUMINUM CLAD ONTO ONE SIDE OF SAID SUPPORT LAYER.
 2. The printing plate as claimed in claim 1, wherein for said support layer the manganese content is in the range of from 0.5 to 2 per cent and for said clad layer the zinc content is in the range of from 0.5 to 2 per cent. 